Does imtranslate do subpixel shifts ?

Question

raheem mian 2020-2-11

回答： Jyothis Gireesh 2020-2-14

x = randi(256,200,200);
y = imtransalte(x,[-20.5 10.3]);

I know that you can specify a decimal when using imtranslate,

but will it actually translate by 10.3 or will it take the nearest integer value when translating ?

Answer 1

Jyothis Gireesh 2020-2-14

Here a few pointers which may be able to help you:

For every pixel position in the output, the algorithm tries to find the corresponding position in the input image. For subpixel shifts, such a pixel position may not exist. In such cases we use interpolation techniques to find the intensity value. In the case of ‘imtranslate’ there are techniques available: ‘cubic’, ‘linear’ and ‘nearest’.
For ‘cubic’and ‘linear’, the intensity value is calculated as a function of the neighboring values. In this case it may not considered as a rounding-off process.
But for ‘nearest’ method, the translation may be considered as being approximated to the nearest full pixel increment.

Hope this helps!!